合并排序

合并排序，将两个已经排序的数组合并成一个数组,此示例仅能合并由小到大排序的数组.

1/合并生成一个新的数组;

#include <iostream>
#include <stdio.h>
using namespace std;

void mergeArray(int *a,int aLen,int *b,int bLen,int *c)
{
    int len = aLen + bLen -1;        //指向a数组的最后一个元素
    aLen--;
    bLen--;
    while(aLen>=0&&bLen>=0)
    {
        if(a[aLen]>b[bLen])
            c[len--] = a[aLen--];
        else
            c[len--] = b[bLen--];            
    }
    while(aLen>=0)
    {
        c[len--] = a[aLen--];
    }
    while(bLen>=0)
    {
        c[len--] = b[bLen--];
    }
}


int main(int argc, char *argv[])
{

    int a[] = {1,2,3,6,17};
    int b[] = {7,8,10,21};
    int c[9];
    mergeArray(a,5,b,4,c);
    return true;
}

2/其中一个数组能容下两个数组的所有元素;

#include <iostream>
#include <stdio.h>
using namespace std;

void mergeArray(int *a,int aLen,int *b,int bLen)
{
    int len = aLen + bLen -1;        //指向a数组的最后一个元素
    aLen--;
    bLen--;
    while(aLen>=0&&bLen>=0)
    {
        if(a[aLen]>b[bLen])
            a[len--] = a[aLen--];
        else
            a[len--] = b[bLen--];            
    }
    while(bLen>=0)
    {
        a[len--] = b[bLen--];
    }
}


int main(int argc, char *argv[])
{

    int a[] = {1,2,3,6,17,0,0,0,0};
    int b[] = {7,8,10,21};
    mergeArray(a,5,b,4);

    return true;
}

 3.链表合并排序,将两个数序链表组合到一个链表中

#include <iostream>
#include <stdio.h>
using namespace std;
struct NodeL
{
    int value;
    NodeL *next;
    NodeL(int value_=0,NodeL *next_=NULL):value(value_),next(next_){}  
};
NodeL *MergeList(NodeL *head1,NodeL *head2)
{
    if(head1==NULL)
        return head2;
    if(head2==NULL)
        return head1;
    NodeL *head = NULL;
    if(head1->value<head2->value)
    {
        head = head1;
        head1 = head1->next;
    }
    else
    {
        head = head2;
        head1 = head2->next;
    }
    NodeL *tmpNode = head;

    while(head1&&head2)
    {
        if(head1->value<head2->value)
        {
            head->next = head1;
            head1 = head1->next;
        }
        else 
        {
            head->next = head2;
            head2 = head2->next;
        }
        head = head->next;
    }
    if(head1)
    {
        head->next = head1;
    }
    if(head2)
    {
        head->next = head2;
    }
    return tmpNode;
}
void test()
{
    NodeL *head1 = new NodeL(1);
    NodeL *cur = head1;
    for(int i=1;i<5;i++)
    {
        NodeL *tmpNode = new NodeL(i); 
        cur->next = tmpNode;
        cur = cur->next;
    }
    NodeL *head2 = new NodeL(2);
    cur = head2;
    for(int i=11;i<35;i+=2)
    {
        NodeL *tmpNode = new NodeL(i);
        cur->next = tmpNode;
        cur = cur->next;
    }

    NodeL *head = MergeList(head1,head2);
    NodeL *headDelete = head;
    while(head)
    {
        cout<<head->value<<" ";
        head = head->next;
    }
    NodeL *tmp;
    while(headDelete)            //没有它是会内存泄漏的
    {
        tmp = headDelete;
        headDelete = headDelete->next;
        delete tmp;
    }
}

int main()
{
    test();
    return 0;
}

 检验一个数组是否是按序排列

#include <iostream>
using namespace std;
int IsOrder(int num[],int lenth)
{
    if(lenth == 1) return 1;
    int k=0;
    for(int i=0;i<lenth-1;i++)
    {
        if(num[i]<num[i+1])
        {
            if(0==k)
            {
                k=1;
            }
            else if(-1==k)
                return 0;
        }
        else if(num[i]>num[i+1])
        {
            if(0==k)
            {
                k=-1;
            }
            else if(1==k)
            {
                return 0;
            }
        }
        
    }
    if (0==k)
        {
            return 1;
        }
    return k;
    
}

int main()
{
    int a[]={1,1,2,3,4,5,8,9};
    int b[]={1,1,2,3,4,5,8,3};
    int c[]={5,4,3,2,1,0,0};
    cout<<IsOrder(a,8)<<endl;
    cout<<IsOrder(b,8)<<endl;
    cout<<IsOrder(c,7)<<endl;
}